Compositions and methods for processing textile fibers



Patented Mar. 25,1952

COMPOSITIONS AND METHODS FOR PROC- ESSING TEXTILE FIBERS Basil G. Skalkeas, Lowell, Mass., assignor to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Application June 24, 1949, Serial No. 101,263

9 Claims. (01. 252--8.6)

The present invention relates to textile fiber processing compositions, and it more particularly relates to compositions for application to cotton fibers prior to carding. This inventionalso relates toimproved methods of processing cellulosic textile fibers and particularly cotton fibers.

One object of this invention is to provide stable compositions for improving the inter-fiber friction and the processing of cellulosic textile fibers.

A further object of this invention is to provide stable compositions which when applied to cotton fibers prior to carding improve the inter-fiber friction of the fibers and the tensile strength of yarn spun from such fibers without substantial loss or dusting of the active ingredients of the composition during subsequent processing of the fibers.

A further object of this invention is to provide improved methods of processing cellulosic textile fibers.

Still further objects and advantages of this invention will be apparent from the following description and the appended claims.

The compositions of this invention comprise, in general, a stable mixture of an alkaline reacting silica aquasol, a small amount of a water-soluble or water-emulsifiable oil lubricant such as a mineral oil sulfonate or a mixture of mineral oil and a mineral oil sulfonate, and a small amount of an organic hygroscopic agent such as propylene glycol. A small amount of wetting agent such as an alkyl benzene alkali metal sulfonate may. also be used.

The term stable as used herein is intended to designate compositions in which the silica, which is in a colloidal state, does not set up as a gel or precipitate from the compositions on standing for periods as long as 6 to 12 months. The compositions described herein have a tendency to cream on standing for 30 days or more, thatis, the oil lubricant phase may tend to rise-to the surface. However, in such instances the compositions are readily rendered homogeneous by simple agitation.

The alkaline reactin silica aquasols referred to herein have a pH (as measured by the glass electrode) between 8 and 11 and consist essentially of water and colloidal silica, the silica being present in amounts within the range between and 45% by weight. It is preferred, however, to

employ alkaline reacting silica aquesols having a pH between 9.0 and 10.5, and containing between and 35% by weight of colloidal silica. These silica aquasols are stable for periods of 12 months and longer and are infinitely dilutable with water without precipitation of silica. The silica is present in such aquasols and in the compositions described herein in the form of discrete, ultramicroscopic particles or agglomerates having particle diameters between about 40 millimicrons and 1 micron.

As examples of water-soluble oil lubricants which are employed in the compositions of this invention may be mentioned mineral oil alkali sulfonates, vegetable oil alkali sulfates and sulfonates such as olive oil alkali sulfates or sulfonates, fatty alcohol alkali sulfates or sulfonates, sulfonated lard oil and the like. As examples of water-emulsifiable oil lubricants which are employed in the compositions of this invention may be mentioned mixtures of mineral oils (otherwise known as petroleum oils) with emulsifying agents such as water soluble and oil soluble mineral oil alkali sulfonates (otherwise known as mahogany soaps), sulfonated lard oil, polyglycol esters of fatty acids containing from 10 to 20 carbon atoms, triethanol amine oleate, turkey red oil, fatty alcohol alkali sulfates or sulfonatesand mixtures of such emulsifying agents; mixtures of vegetable oils such as olive oil with such emulsifying agents; lard oil; emulsified paraffin waxes; and mixtures of mineral oil, fatty oils such as animal and vegetable oils, and mineral oil alkali sulfonates or other emulsifying agents of the type described above. The above mixtures comprise, in general, from to by weight of oil and from 35 to 5% by weight of the emulsifying agent or of a mixture of the emulsifying agents. Of the above described oil lubricants a Water-emulsifiable mixture of mineral oil and mineral oil alkali sulfonate, or a water-emulsifiable mixture of mineral oil, vegetable oil and a mineral oil alkali sulfonate are preferred. The term water-emulsifiable as used herein is intended to designate oil lubricants which possess the property of forming a relatively stable oil-in-water emulsion on simple or vigorous agitation.

As examples of organic hygroscopic agents which are employable in the compositions of this invention may be mentioned polyhydric alcohols such as glycerine, sorbitol, ethylene glycol, 2 methyl-2,4 pentanediol and the like; polyhydric alcohols containing ether linkages as, for example, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tetraethylene glycol, polyethylene glycol, having the formula HOCH2(CH2-O-CH2) xCHzOH in which X is an integer from 5 to 12, and the like; amines such as monoethanol amine, triethanol amine and the like; and acetamide and the like. Of the above organic hygroscopic agents propylene glycol and diethylene glycol are preferred. By organic hygroscopic agent is meant an organic compound or a mixture of organic compounds which is capable of absorbing and retaining at least 100% of its own weight of water either from water of solution or from water in the atmosphere.

The colloidal silica present in the compositions of this invention serves to increase the interfiber friction of unspun cellulosic textile fibers when applied thereto. Thus the colloidal silica serves to increase the tensile strength of yarns spun from cellulosic fibers treated therewith. Other advantages resulting from the use of colloidal silica on unspun cellulosic textile fibers include: an increased rate of spinning as compared to untreated fibers; a reduction in the number of turns per inch required as compared to untreated fibers; stronger and more uniform webs and slivers.

The water-emulsifiable or water-soluble oil lubricant and the hygroscopic agent serve as a carrier for the colloidal silica thereby enabling the colloidal silica to adhere to the fibers during application and the subsequent processing or mechanical manipulation of the fibers. The oil lubricant and the organic hygroscopic agent thus serve to bind the colloidal silica particles to the fiber so that verv little or no silica is lost through dusting during the subsequent mechanical manipulation of the fibers. In general, the oil lubricant and hygroscopic agent are used in an amount sufficient to bind the colloidal silica to the fibers, but insufficient to decrease=the interfiber friction of the fibers obtained by the use of the colloidal silica per se. Satisfactory results are obtained by using from 15 to 75% by weight, based on the weight of silica in the aquasol, of the water-soluble or water-emulsifiable oil lubricant, and from 15 to 75% by weight, based on the weight of silica in the aquasol, of the organic hygroscopic agent. Superior results are obtained by using from 25 to 50% by weight, based on the weight of silica in the aquasol, of the oil lubricant and from 25 to 50% by Weight, based on the weight of silica in the aquasol, of the organic hy roscopic a ent.

The com ositions of this invention are generallv applied to unspun cellulosic textile fibers at some stage of their processing prior to carding, that is. at any point in the opening and picking line. However, the compositions are preferably applied to the fibers at some point bet een the opener and the picker and more particularly in the pneumatic trunk line between the cleaners and the condenser feeding t e picker. The com positions are preferably applied to the fibers by sprayin but other means of a plication may be used. Amounts of the composition sufficient to apply from 011 to 3% by weight of silica, from 0.1 to 0.8% by weight of the oil lubricant and from 0.1 to 0.3% b wei ht of hygroscopic a ent should be used. These percentages are based on the weight of the fibers. The application of such amounts of the composition does not interfere with the cleaning and opening of the stock prior to carding. It is preferred to use the compositions in as concentrated a form as possible and thus avoid the addition of appreciable amounts of water.

The oil lubricant and hygroscopic agent, in addition to acting as a carrier for the colloidal silica, help to distribute the colloidal silica more uniformly throughout the fibers during the a plication of the composition to the fibers. This means that the individual fibers tend to respond uniformly during subsequent mechanical manipulations and thus enable the production of uniform webs and slivers. Yarns produced from the treated fibers also tend to have improved elasticity as compared to yarns produced from fibers treated with colloidal silica per se.

After the compositions of this invention have been applied to cellulosic textile fibers, as described above, the fibers are processed as carded stocks in the normal way, that is, they are first formed into a lap and are then carded, drawn, roved and spun or they are processed as combed stocks inthe normal way, that is, they are carded, drawn, sliver doubled, lap doubled, combed, roved and spun. During the drawing, roving and spinning operations the equipment used is preferably adjusted to compensate for the increased interfiber friction of the partially formed yarn.

The silica aquasols, hereinbefore, described, may be prepared in various ways. A suitable process for preparing such aquasols consists in reacting a mineral acid such as sulfuric acid with a water-soluble silicate such as sodium silicate until an acid reacting sol is obtained. The sol soon sets up into a gel which is broken up into lumps and washed with water to remove the electrolytes formed during the reaction between the acid and the silicate. The washed gel is covered with a weak aqueous solution of a substance capable of forming hydroxyl ions, for example, sodium hydroxide. After the gel has absorbed the hydroxyl ions, it is separated from the excess solution and is heated, while avoiding the evaporation of water, for example, in an autoclave until the maior portion of the gel is converted to a sol. The sol is then separated from any unconverted gel as, for example, by centrifuging. The above process is described in greater detail in Example I, which appears hereinafter, and in the patent to John F. White, No. 2,375,738, granted May 8, 1945. It is also possible to use silica aquasols prepared by treating an alkali silicate with a cation-exchange material, as described in the patent to Paul C. Bird, No. 2,244,325, providing of course it is adjusted to the proper pH, as hereinbefore defined.

A further understanding of this invention will be obtained from the following specific examples which illustrate various compositions and their application to textile fibers, parts and percentages being by weight.

Example I Alkaline reacting silica aquasol was prepared as follows:

Seventy-three parts of 66 B. H2804 were diluted with 358 parts of water and char ed to a mixing tank. Four hundred and seventy-two parts of an aqueous sodium silicate solution analyzing 8.9% NazO and 29% SiO2 were diluted with 377 parts of water. The silicate solution was added with stirring to the acid solution. The resulting mixture set up as a gel in a few minutes after the mixing was completed. After the gel had aged for 16 hours the syneresis licuor was drained off and the gel was crushed to one-inch lumps. The gel lumps were washed with a continuous flow of water for 16 hours and were then covered with 750 parts of water containing 0.9 parts of NaOH. After standing for 6 hours the solution was drained off and a portion of the gel lumps were charged to an autoclave equipped with a steam jacket. The gel was heated for 4 flours, using steam at 21 5;ppnnds per square inch absolute pressure in the jacket of the autoclave. The contents of the autoclave were then blown out and the residual undispersed gel was removed from the resulting sol by centrifuging.

form, without separation of the ingredients, for

a period of at least 30 days.

The above composition was sprayed, in the form or" fine droplets, on cotton fibers in the pneumatic trunk line between the cleaners and the condenser feeding the picker in an amount suiiicient to deposit 2% of the composition, based on the weight of the fibers. The fibers were then processed into yarns in the normal manner during: which processing they exhibited considerable inter-fiber friction. The resulting yarns possessed increased tensile strength as compared to similar yarns prepared from untreated fibers. The colloidal silica adhered to the fibers during the processing operations and did not dust off to any appreciable extent.

Example I! A silica aquasol was prepared as described in Example I and was then concentrated by boiling off water until it contained 15% SiOz. Thirtysix'i parts of the resulting aquasol were stirred rapidly together with 2 parts of a water-emulsifiable lubricant consisting of a mixture of mineral oil, vegetable oil and mineral oil sodium sulfonate, and 2 parts of propylene glycol.

The resulting composition was sprayed, in the form of fine droplets, on very low grade cotton fibers in the final beater section of a picker in an amount suflicient to deposit 0.6 SiOz, 0.25% of the lubricant and 0.25% of the glycol, all based on the weight of cotton fibers. The treated fibers were formed into a lap and then carded in the customary manner. On the card the web showed a better parallelization of the fibers than is customary in the case of untreated fibers. The card sliver exhibited a harsher hand, increased drag of the fibers and increased tensile strength compared to a control produced from untreated fibers. The card sliver was then further processed, that is, it was drawn, slubbed, processed on an intermediate frame, roved and then spun as s yarn using a twist multiple of 4.50. The silica did not dust oh" the fibers to any appreciable extent during the above processing operations. The resulting yarn had a tensilelstrength of 180.5 pounds after it had been conditioned in an atmosphere of 70 F. and 65% relative humidity for 24 hours. A control 10s yarn produced from untreated fibers, spun at a twist multiple of 5.05, and conditioned in the same manner, only had a tensile strength of 172.7 pounds.

Example H I An alkaline reacting silica aquasol was prepared as follows:

An aqueous sodium silicate solution (in which the silica and NazO were present in a weight ratio of 3.4 to 1) containing about 3% of combined S102 was allowed to flow by gravity at the rate of 250 parts per minute through a 12-inch deep bed of acid regenerated cation-exchange material, contained in a cylindrical glass tube having an internal diameter of approximately 1% inches. The silicate solution was allowed to flow through the bed of material until the total efiluent issuing therefrom had a pH of 9.5. The resulting sol was then boiled until it contained about 20% colloidal silica.

Thirty parts of the above silica aquasol were stirred rapidly with 3 parts of a water-emulsifieble oil lubricant consisting of a mixture of mineral oil and mineral oil sodium sulfonate, and 3 parts of diethylene glycol. The composition was then diluted until it contained 10% SiOz.

The resulting composition was sprayed, in the form of fine droplets, on very low grade cotton fibers in the final beater section of a picker in an amount sufficient to deposit 3% of the composition, based on the weight of the cotton fibers. The treated fibers were then processed into yarns in the normal manner. During carding the web exhibited better parallelization of fibers and was stronger than a web produced from a control of untreated fibers. The card sliver was more compact, harsher and exhibited greater inter-fiber friction or drag and increased tensile strength compared to a control of untreated fibers. During the subsequent processing operations such as drawing, slubbing, intermediate frame operations, roving and spinning the treated fibers exhibited considerable inter-fiber friction or drag and the finished yarn possessed improved tensile strength compared to a control of untreated fibers. Moreover, during all of the foregoing processing operations very little dusting of the silica from the fibers was observed.

Example IV I A composition containing 30 parts of alkaline reacting silica aquasol (the 20% sol prepared as described in Example III), 2.4 parts of propylene glycol, and 2.4 parts of a water-emulsifiable oil lubricant consisting of 78% mineral oil, 20% sulfonated lard oil and 2% triethanolamine oleate was applied, in the form of fine droplets, on cotto'n fibers in the final beater section of the picker in an amount sufficient to deposit 2% of the composition based on the weight of fibers. The treated fibers were then processed into yarns as described in Example III. During such processing they exhibited greater inter-fiber friction or drag and the finished yarn possessed improved tensile strength compared to a control of untreated fibers. Moreover, very little dusting of the silica from the fibers was noted during the processing of the fibers into yarns.

Various changes and modifications may be made in the compositions and processes described herein, as will be apparent to those skilled in the art, without departing from the spirit of this invention, and it is intended that this invention be limited only by the scope of the appended claims.

What is claimed is:

1. A composition for application to cellulosic textile fibers prior to carding comprising a stable mixture of an alkaline reacting silica aquasol containing from 5 to 45% by weight of colloidal silica, from 15 to 75% by weight, based on the weight of silica in the aquasol, of a substance selected from the group consisting of water-soluble and water-emulsifiable oil lubricants, and from 15 to 75% by weight, based on the weight of silica in the aquasol, of an organic hygroscopic agent.

2. A composition for application to cellulosic textile fibers prior to carding comprising a stable mixture of a silica aquasol containing from to 45% by weight colloidal silica and having a pH between 8 and 11, from to 75% by weight, based on the weight of silica in the aquasol, of a substance selected from the group consisting of water-soluble and water-emulsifiable oil lubricants, and from 15 to 75% by weight, based on the weight of silica in the aquasol, of an organic hygroscopic agent.

3. A composition for application to cellulosic textile fibers according to claim 2, but further characterized in that the oil lubricant is a mixture of a mineral oil and a mineral oil alkali sul- 'fonate.

4. A composition for application to cellulosic textile fibers according to claim 2, but further characterized in that the oil lubricant is a mixture of mineral oil, vegetable oil and a mineral oil alkali sulfonate.

5. A composition for application to cellulosic textile fibers according to claim 2, but further characterized in that the hygroscopic agent is propylene glycol.

6. A composition for application to cellulosic textile fibers according to claim 2, but further characterized in that the hygroscopic agent is diethylene glycol.

7. In the method of processing cellulosic textile fibers into yarns, the improvement which consists in applying to the fibers at some stage of their processing prior to carding a composition in the form of fine droplets, comprising a mixture of (-1) an alkaline reacting silica aquasol containing from 5 to 45% by weight of colloidal silica, (2) from 15 to 75% by weight, based on the weight of silica in said aquasol, of a substance selected from the group consisting of water-soluble and water-emulsifiable oil lubricants and (3) from 15 to 75% by weight, based on the weight of the silica in said aquasol, of an organic hygroscopic agent, said composition being applied in an amount sufi'icient to deposit from 0.1 to 3% by weight of silica, from 0.1 to 0.3% by weight of said substance and from 0,1 to 0.3% by weight 8 of said agent, all of the latter percentages by weight being based on the weight of the fibers.

8, A method according to claim 7, but further characterized in that the organic hygroscopic agent is propylene glycol.

9. In the method of processing cotton fibers into yarns, the improvement which consists in applying to the fibers in the pneumatic trunk line between the cleaners and the condenser feeding the picker a composition, in the form of fine droplets, comprising a mixture of (1) an alkaline reacting silica aquasol containing from 5 to by weight of colloidal silica, (2) from 15 to by weight, based on the weight of silica in said aquasol, of a substance selected from the group consisting of water-soluble and water-emulsifiable oil lubricant and (3) from 15 to 75% by weight, based on the weight of silica in said aquasol, of an organic hygroscopic agent, said composition being applied in an amount suflicient to deposit from 0.1 to 3% by weight of silica, from 0.1 to 0.3% by weight of said substance and from 0.1 to 0.3% by weight of said agent, all of the latter percentages byweight being based on the weight of the fibers.

BASIL G. SKALKEAS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Reinhold Pub. Corp., N. Y. pgs. 1114-1115, vol. VI.

Textile Finishing, Marsh, 1948, pub. Chapman & Hall Ltd, London, pg. 273. 

1. A COMPOSITION FOR APPLICATION TO CELLULOSIC TEXTILE FIBERS PRIOR TO CARDING COMPRISING A STABLE MIXTURE OF AN ALKALINE REACTING SILICA AQUASOL CONTAINING FROM 5 TO 45% BY WEIGHT OF COLLOIDAL SILICA, FROM 15 TO 75% BY WEIGHT, BASED ON THE WEIGHT OF SILICA IN THE AQUASOL, OF A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF WATER-SOLUBLE AND WATER-EMULSIFIABLE OIL LIBRICANTS, AND FROM 15 TO 75% BY WEIGHT, BASED ON THE WEIGHT OF SILICA IN THE AQUASOL, OF AN ORGANIC HYGROSCOPIC AGENT. 